<template>
  <div class="box">
    <h1>Child</h1>
    <input type="text" :value="value" @input="$emit('input',$event.target.value)">
    <button @click="$emit('input',value+1)">修改父组件的值</button>
  </div>
</template>

<script>
export default {
    name:'Child',
    props:['value']
}
</script>

<style scoped>
    .box{
        background: yellowgreen;
    }
</style>